“If the U.S. is trying to drive us into a corner to force our unilateral nuclear abandonment, we will no longer be interested in such dialogue and cannot but reconsider our proceeding to the DPRK-U.S. summit,” said the translated statement attributed to Kim Kye Gwan, North Korea’s first vice-minister of Foreign Affairs.

Trump announced last week he would meet with Kim on June 12 in Singapore to discuss an agreement on nuclear weapons. For months, the American president has urged China and other countries to cut off economic aid to North Korea until Kim gives up his weapons programs.

In its latest statement, the North Koreans suggested they would not give up nukes even in exchange for economic assistance from the U.S. and allies.

The statement attacked Trump aides, singling out National Security Adviser John Bolton in particular, for promoting what the North Koreans called “the assertions of so-called Libya mode of nuclear abandonment.”

Libyan leader Muammar Gadhafy gave up programs for weapons of mass destruction in 2003. He was deposed and killed in 2011 after a rebellion sparked by the Arab Spring.

The U.S.-led invasion of Iraq in 2003, based on faulty intelligence about weapons of mass destruction, toppled Saddam Hussein’s government.

In an earlier statement, North Korea criticized ongoing joint military exercises by the United States and South Korea, and said that was a reason to rethink the Trump-Kim summit.

U.S. officials, caught by surprise, said they have received no formal notification from the North or South Korean governments, and no formal protest of the military exercises from Kim’s government.

Sanders said the administration “will look at what North Korea has said independently, and continue to coordinate closely with our allies.”

The U.S. Defense Department said the military exercises are annual events, designed to help the U.S.-South Korea alliance defend itself in case of attack. “While we will not discuss specifics, the defensive nature of these combined exercises has been clear for many decades and has not changed,” said Army Col. Robert Manning, a Pentagon spokesman.

The North Koreans went ahead and canceled planned meetings Wednesday with South Korean counterparts. The two sides had planned to discuss new efforts to reduce border tensions, including proposals to re-unite families separated during the Korean War of the early 1950s.

The South and North Koreans have also talked about a formal peace treaty, as they are technically still at war; the original Korean conflict ended with an armistice signed in 1953.

In announcing the cancellation of the meeting with the South Koreans, the North Koreans said that “the United States will also have to undertake careful deliberations about the fate of the planned North Korea-U.S. summit in light of this provocative military ruckus jointly conducted with the South Korean authorities.”

In its latest threat to cancel the Trump-Kim summit, the North Koreans took aim at Trump’s reputation and alluded to his criticism of previous presidents over their handling of Korean issues.

“If President Trump follows in the footsteps of his predecessors, he will be recorded as more tragic and unsuccessful president than his predecessors, far from his initial ambition to make unprecedented success,” said the translated statement.